Interpretation of the spectroscopic properties of α-LiAlO₂: Mn⁴⁺

The energy position of the ²Eg→⁴A_2g emission transition of Mn⁴⁺ in α-LiAlO₂ is identified and the electronic energy levels calculated using the exchange charge model of crystal field theory. The results of our calculations yield the crystal field splitting and Racah parameters of Dq = 2351 cm^-1, B = 650 cm^-1 and C = 3469 cm^-1, with C/B = 5.3. The calculated Mn⁴⁺ energy levels are in good agreement with the experimental spectra that have been presented in the literature. A study that develops the relationship between the energy of the ²Eg state with the connectivity of the octahedral moieties and deviation of O-Mn-O bond angle in the equatorial plane from the ideal value of 90° is presented.